U.S. life expectancy jumped last year, and preliminary data suggests there may be another — much smaller — improvement this year.

Death rates fell last year for almost all leading causes, notably COVID-19, heart disease and drug overdoses, according to the Centers for Disease Control and Prevention report released Thursday. That translated to adding nearly a year the estimated lifespan of Americans.

Experts note it's part of a bounce-back from the COVID-19 pandemic. But life expectancy has not yet climbed back to prepandemic levels, and the rebound appears to be losing steam.

"What you're seeing is continued improvement, but slowing improvement," said Elizabeth Wrigley-Field, a University Minnesota researcher who studies death trends. "We are sort of converging back to some kind of normal that is worse than it was before the pandemic."

Last year, nearly 3.1 million U.S. residents died, about 189,000 fewer than the year before. Death rates declined across all racial and ethnic groups, and in both men and women.

Provisional data for the first 10 months of 2024 suggests the country is on track to see even fewer deaths this year, perhaps about 13,000 fewer. But that difference is likely to narrow as more death certificates come in, said the CDC's Robert Anderson.

That means that life expectancy for 2024 likely will rise — "but probably not by a lot," said Anderson, who oversees death tracking at the CDC’s National Center for Health Statistics.

Life expectancy is an estimate of the average number of years a baby born in a given year might expect to live, given death rates at that time. It's a fundamental measure of a population's health.

For decades, U.S. life expectancy rose at least a little bit almost every year, thanks to medical advances and public health measures. It peaked in 2014, at nearly 79 years, and then was relatively flat for several years. Then it plunged during the COVID-19 pandemic, dropping to just under 76½ years in 2021.

It rebounded to 77½ years in 2022 and, according to the new report, to nearly 78½ last year.

Life expectancy for U.S. women continues to be well above that of men — a little over 81 for women, compared with a little under 76 for men.

In the last five years, more than 1.2 million U.S. deaths have been attributed to COVID-19. But most of them occurred in 2020 and 2021, before vaccination- and infection-induced immunity became widespread.

The coronavirus was once the nation's third leading cause of death. Last year it was the underlying cause in nearly 50,000 deaths, making it the nation's No. 10 killer.

Data for 2024 is still coming in, but about 30,000 coronavirus deaths have been reported so far. At that rate, suicide may surpass COVID-19 this year, Anderson said.

Heart disease remains the nation’s leading cause of death. Some underappreciated good news is the heart disease death rate dropped by about 3% in 2023. That’s a much smaller drop than the 73% decline in the COVID-19 death rate, but heart disease affects more people so even small changes can be more impactful, Anderson said.

There's also good news about overdose deaths, which fell to 105,000 in 2023 among U.S. residents, according to a second report released by CDC on Thursday.

The causes of the overdose decline are still being studied but there is reason to be hopeful such deaths will drop more in the future, experts say. Some pointed to survey results this week that showed teens drug use isn't rising.

"The earlier you start taking a drug, the greater the risk that you could continue using it and the greater the risk that you will become addicted to it — and have untoward consequences," said Dr. Nora Volkow, director of the National Institute on Drug Abuse, which funded the survey study. "If you can reduce the pipeline (of new drug users) ... you can prevent overdoses."